The long-term goal of this proposal is to determine the precise role of myocilin in the human body and to develop an assay for specific, dominant affects of mutant myocilin forms. Myocilin is a product of the GLCIA gene and has been identified as a protein responsible for inducing the onset of the adult and juvenile forms of primary open angle glaucoma (POAG and JOAG, respectively). Many of the glaucoma-inducing mutations identified in the GLCIA gene occur in the evolutionarily conserved C-terminal half of the protein, the olfactomedin domain. Despite a wealth of information about the structure of the olfactomedin domain and the structure of the human myocilin protein, nothing is known about the function of myocilin in the body. We have performed sequence analysis of the Caenorhabditis elegans genome, identified two hypothetical proteins that are highly homologous to the C-terminal half of human myocilin, and shown that both of these proteins are expressed in wild-type animals. We believe C. elegans will be an excellent system for determining the genetic and developmental roles of myocilin. Therefore, in the present study we propose the following specific aims. First, we will determine temporal and spatial expression patterns of each of the C. elegansgenes in wild-type animals using molecular techniques to monitor protein and RNA accumulation. Second, we will determine what roles the myocilin proteins play in C. elegansdevelopment by interfering with gene expression and determining the phenotypic variance that occurs as a result of the interference. We will also determine if the human myocilin protein is able to compensate for the loss of the C. elegans genes. Finally, we will determine how mutations in the human myocilin protein affect the expression and function of the C. elegans genes by expressing mutant human forms in wild-type animals. Together, the data generated in this proposal will serve as an impetus for further research into the function of myocilin in the body.